The present invention relates generally to a cargo or freight container and more particularly to a weatherproof or waterproof system for preventing intrusion of rain or sea water along the intersurface between the floor and the side walls of the container into the interior thereof, thereby preventing loaded cargoes from becoming wet and damaged.
In general, cargo or freight containers which are transportable comprise a generally rectangular floor panel, four side panels and a roof panel. Such containers must be provided with suitable weatherproof or waterproof means so that cargoes therein are prevented from becoming wet and damaged by rain or sea water. The weatherproof systems for cargo or freight containers which are not foldable or collapsible are relatively simple in construction and easy to install, but those for foldable or collapsible containers of the type in which four side panels can be folded over the floor panel, one upon another, are complicated in construction and difficult to make fully weatherproof because the foldable or collapsible containers have many surfaces of contact between the floor, side and roof panels which are not permanently and water-tightly joined together. In the prior art foldable or collapsible containers, resilient sealing means such as rubber packings are interposed in the joints between the floor, side and roof panels when they are assembled, thereby water-tightly sealing the container.
The use of packing members is very effective in providing a weatherproof system, but it has some disadvangages or defects as will be described below. Firstly, they are much softer than the materials such as steels of the structural components, that is, the floor, side and roof panels so that in the loading and unloading of the containers, inevitable collisions with "foreign bodies" often cause puncturing of packing members with the resultant water hazard. Secondly, the service life of the packings is very short as compared with the container structural components such as floor, side and roof panels. Therefore, during a long period of use, the packing members deteriorate so that they cannot ensure desired water-tight sealing function. Accordingly, the packing members must be periodically inspected and replaced if damage is found. Therefore, in some cases, the foldable containers with cargoes loaded therein are completely covered with sheet covers so as to protect them from rain or sea water during transportation and outdoor storage.